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Article
Publication date: 21 February 2020

Tanmay Basak

This paper aims to investigate the thermal performance involving larger heating rate, targeted heating, heating with least non-uniformity of the spatial distribution of…

178

Abstract

Purpose

This paper aims to investigate the thermal performance involving larger heating rate, targeted heating, heating with least non-uniformity of the spatial distribution of temperature and larger penetration of heating within samples vs shapes of samples (circle, square and triangular).

Design/methodology/approach

Galerkin finite element method (GFEM) with adaptive meshing in a composite domain (free space and sample) is used in an in-house computer code. The finite element meshing is done in a composite domain involving triangle embedded within a semicircular hypothetical domain. The comparison of heating pattern is done for various shapes of samples involving identical cross-sectional area. Test cases reveal that triangular samples can induce larger penetration of heat and multiple heating fronts. A representative material (beef) with high dielectric loss corresponding to larger microwave power or heat absorption in contrast to low lossy samples is considered for the current study. The average power absorption within lossy samples has been computed using the spatial distribution and finite element basis sets. Four regimes have been selected based on various local maxima of the average power for detailed investigation. These regimes are selected based on thin, thick and intermediate limits of the sample size corresponding to the constant area of cross section, Ac involving circle or square or triangle.

Findings

The thin sample limit (Regime 1) corresponds to samples with spatially invariant power absorption, whereas power absorption attenuates from exposed to unexposed faces for thick samples (Regime 4). In Regimes 2 and 3, the average power absorption non-monotonically varies with sample size or area of cross section (Ac) and a few maxima of average power occur for fixed values of Ac involving various shapes. The spatial characteristics of power and temperature have been critically analyzed for all cross sections at each regime for lossy samples. Triangular samples are found to exhibit occurrence of multiple heating fronts for large samples (Regimes 3 and 4).

Practical implications

Length scales of samples of various shapes (circle, square and triangle) can be represented via Regimes 1-4. Regime 1 exhibits the identical heating rate for lateral and radial irradiations for any shapes of lossy samples. Regime 2 depicts that a larger heating rate with larger temperature non-uniformity can occur for square and triangular-Type 1 lossy sample during lateral irradiation. Regime 3 depicts that the penetration of heat at the core is larger for triangular samples compared to circle or square samples for lateral or radial irradiation. Regime 4 depicts that the penetration of heat is still larger for triangular samples compared to circular or square samples. Regimes 3 and 4 depict the occurrence of multiple heating fronts in triangular samples. In general, current analysis recommends the triangular samples which is also associated with larger values of temperature variation within samples.

Originality/value

GFEM with generalized mesh generation for all geometries has been implemented. The dielectric samples of any shape are surrounded by the circular shaped air medium. The unified mesh generation within the sample connected with circular air medium has been demonstrated. The algorithm also demonstrates the implementation of various complex boundary conditions in residuals. The numerical results compare the heating patterns for all geometries involving identical areas. The thermal characteristics are shown with a few generalized trends on enhanced heating or targeted heating. The circle or square or triangle (Type 1 or Type 2) can be selected based on specific heating objectives for length scales within various regimes.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 July 1999

Stuart James

16

Abstract

Details

Reference Reviews, vol. 13 no. 7
Type: Research Article
ISSN: 0950-4125

Keywords

Article
Publication date: 10 July 2023

Fatimah De’nan, Chong Shek Wai and Nor Salwani Hashim

Various designs of corrugated webs include trapezoidal, sinusoidal, triangular and rectangular profiles. The increasing use of curved plates has prompted the creation of…

Abstract

Purpose

Various designs of corrugated webs include trapezoidal, sinusoidal, triangular and rectangular profiles. The increasing use of curved plates has prompted the creation of I-sections made of steel with a corrugated web design. This study aims to examine the effectiveness of an I-beam steel section that features a perforated-triangular web profile.

Design/methodology/approach

In the current study, finite element analysis was conducted on corrugated-perforated steel I-sections using ANSYS software. The study focused on inspecting the design of the perforations, including their shape (circle, square, hexagon, diamond and octagon), size of perforations (80 mm, 100 mm and 120 mm) and layout (the position of web perforation), as well as examining the geometric properties of the section in term of bending, lateral torsional buckling, torsion and shear behavior.

Findings

The study revealed that perforations with diamond, circle and hexagon shapes exhibit good performance, whereas the square shape performs poorly. Moreover, the steel section’s performance decreases with an increase in perforation size, regardless of loading conditions. In addition, the shape of the web perforations can also influence its stress distribution. For example, diamond-shaped perforations have been found to perform better than square-shaped perforations in terms of stress distribution and overall performance. This was because of their ability to distribute stress more evenly and provide greater support to the surrounding material. The diagonal alignment of the diamond shape aligns with principal stress directions, allowing for efficient load transfer and reduced stress concentrations. Additionally, diamond-shaped perforations offer a larger effective area, better shear transfer and improved strain redistribution, resulting in enhanced structural integrity and increased load-carrying capacity.

Originality/value

Hence, the presence of lateral-torsional buckling and torsional loading conditions significantly impacts the performance of corrugated-perforated steel I-sections.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 August 1997

Gerald Heidegger

Views new tasks of vocational education and training (VET) from the perspective of the German educational system for the upper secondary level. Outlines a proposal to enrich the…

1185

Abstract

Views new tasks of vocational education and training (VET) from the perspective of the German educational system for the upper secondary level. Outlines a proposal to enrich the German “dual system” of vocational education with elements of “general” education. Important effects on VET are to be expected. The main means for such a change should be the guideline of “social shaping of work and technology”. Stresses the importance of “doing” in relation to “thinking”. This “shaping approach” shows to be a starting point for a new curricular theory. Sketches the problem of legitimizing criteria for shaping work and technology, making use of dialectical ideas. In conclusion, highlights some consequences for the education of VET professionals.

Details

Journal of European Industrial Training, vol. 21 no. 6/7
Type: Research Article
ISSN: 0309-0590

Keywords

Article
Publication date: 2 August 2019

Yong Cao, Yang Lu, Yueri Cai, Shusheng Bi and Guang Pan

This paper aims to imitate a cownose ray to develop a fish robot with paired flexible multi-fin-ray oscillating pectoral fins (OPFs) and control it to accomplish vivid stable 3-D…

Abstract

Purpose

This paper aims to imitate a cownose ray to develop a fish robot with paired flexible multi-fin-ray oscillating pectoral fins (OPFs) and control it to accomplish vivid stable 3-D motions using central pattern generators (CPGs) and fuzzy algorithm.

Design/methodology/approach

The cownose ray’s asymmetric sine-like oscillations were analyzed. Then a cownose-ray-like fish robot named Robo-ray was developed, which has paired flexible multi-fin-ray OPFs to actively control the fin shape and two tail fins to control the depth. To solve the problem of coordinated control for multi-degree-of-freedom Robo-ray, CPGs were adopted. An improved phase oscillator as a CPG unit with controlled amplitude, phase lag, smooth frequency transition and asymmetric oscillation characteristic was established. Furthermore, the CPG-fuzzy algorithm was developed for vivid stable 3-D motions. The open-loop speed control, the closed-loop control of depth and yaw were established.

Findings

The kinematic comparisons indicate that Robo-ray imitates the cownose ray realistically. The experimental results of closed-loop are obtained that the depth error of Robo-ray is less than ±100 mm and the course error is less than ±3°. Furthermore, the comprehensive experiments demonstrate that Robo-ray has high mobility, stability and robustness.

Originality/value

This research makes the fish robot with OPF propulsion closer to practical applications in complex underwater environment, for instance, ocean explorations, water quality monitoring and stealth military reconnaissance. In addition, Robo-ray can be taken as a scientific tool for better understanding of the hydrodynamics of OPF batoid.

Details

Industrial Robot: the international journal of robotics research and application, vol. 46 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 24 July 2019

Fuying Zhang, Junmei Yang, Haoche Shui and Chengcheng Dong

This paper aims to obtain the film thickness, friction torque and pumping rate and analyze the effects of roughness and surface micro-dimple texture (circular, square and…

Abstract

Purpose

This paper aims to obtain the film thickness, friction torque and pumping rate and analyze the effects of roughness and surface micro-dimple texture (circular, square and equilateral triangle) on the performance of the oil seal.

Design/methodology/approach

On the basis of elastohydrodynamic lubrication and the pumping mechanism of rotating shaft seal, this paper establishes a numerical model of hybrid lubrication of oil seal in sealing area. The model is coupled with fluid mechanics, rough peak contact mechanics and deformation analysis.

Findings

The results show that surface texture significantly improves the lubrication properties of the oil seal. The oil seal with the square texture has the largest oil film thickness, while the equilateral triangle texture has a better effect on the pumping rate.

Originality/value

To get closer to the real working environment of the oil seal, based on the surface roughness, this paper studies the effect of the texture shapes applied to the oil seal lip surface on the performance of the oil seal. The critical roughness and rotational speed values with zero pumping rate are obtained, which provides a theoretical basis for the correct selection of oil seals.

Details

Industrial Lubrication and Tribology, vol. 72 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Open Access
Book part
Publication date: 4 May 2018

Rd. Selvy Handayani and Ismadi

Purpose – The purpose of this study was to invent morphological North Aceh durian data as germplasm information.Methodology – The research was conducted at Langkahan and Sawang…

Abstract

Purpose – The purpose of this study was to invent morphological North Aceh durian data as germplasm information.

Methodology – The research was conducted at Langkahan and Sawang, North Aceh Region, from March to August 2014. The material used was the durian plant that should be 20 years and preferred by the local community. Exploration as the first step of experiment was done by purposive sampling. Identification was done on the source of durian germplasm. The source of durian germplasm as the experimental object was observed for its growth and morphology. Data analysis for morphological characteristics was done by using NTSYSpc (Numerical Taxonomy and Multivariate Analysis) NTSYSpc versi 2.02.

Originality – The results showed that there were 25 accessions superior durian in Langkahan and 26 accessions superior durian in Sawang. They had different characters in the vegetative parts of the plant. The durian coefficient value of similarity in Langkahan ranged from 0.33 to 0.94, while in Sawang, it ranged from 0.24 to 0.86. The diversity of the morphological character in superior durian of Langkahan and Sawang was seen from the qualitative character (surface and color of bark, crown shape, top surface color of leaves, and leaf shape) and quantitative character (plant height, stem diameter, crown diameter, length, width, and leaf area).

Details

Proceedings of MICoMS 2017
Type: Book
ISBN:

Keywords

Article
Publication date: 1 July 1993

Mutawakilu Adisa Tiamiyu

Information products are analysed in terms of their linguistic, artistic, technological, pragmatic and contextual components and characteristics, and illustrated with examples of…

Abstract

Information products are analysed in terms of their linguistic, artistic, technological, pragmatic and contextual components and characteristics, and illustrated with examples of how the components are combined in real‐life information products. The conclusion is that the malleability and versatility of the components, and the technological possibilities of combining them provide seemingly unlimited scope for designing and marketing value‐added information products in our increasingly competitive and information technology‐based societies.

Details

Aslib Proceedings, vol. 45 no. 7/8
Type: Research Article
ISSN: 0001-253X

Abstract

Details

The Lived Experience of Work and City Rhythms: A Rhythmanalysis of London's Square Mile
Type: Book
ISBN: 978-1-83982-759-4

Book part
Publication date: 21 November 2015

Billie Eilam

The chapter discusses my response to the urgent need for a pedagogy that would effectively promote Israeli teachers’ meta-representational and particularly Visual Representational…

Abstract

The chapter discusses my response to the urgent need for a pedagogy that would effectively promote Israeli teachers’ meta-representational and particularly Visual Representational competencies in order to prepare new generations of school students to fully and successfully navigate the diverse, rich multimodal information that they encounter in the postmodern visual world. Currently, although VRs widely permeate school curricula, learners’ mass media sources for information gathering, and even matriculation testing, students’ meta-representational competence (MRC) are not intentionally developed to enable their dealing with visually transmitted information and their mindful manipulation of it for achieving their goals. VRs usages have been shown to be superficial, implicit, inadequate to utilize VRs’ potential for promoting knowledge acquisition and understanding, and even frequently erroneous. Following a short discussion of the constructs of Meta-Visual Representational Competencies and pedagogy, and potential institutional obstacles for introducing VRs, I propose core pedagogical guidelines for promoting such competencies in teachers, based on evidence collected continually over a decade of work with teachers at Haifa, Israel, while designing, developing, and refining this pedagogy in preservice teacher training and other programs at the University of Haifa and inservice frameworks. Each guideline is operationalized into tasks and activities designed for achieving its specific purpose, focusing on the application of these suggested guidelines in preservice teacher development program. The MRC-promoting pedagogy was designed and developed while keeping in mind the notion that a pedagogy should be flexible, adaptable to different instructional styles, goals, and contexts, and based on guidelines that are operationalized into detailed instructional plans for achieving specific goals, in accordance with teachers’ preferences.

Details

International Teacher Education: Promising Pedagogies (Part C)
Type: Book
ISBN: 978-1-78441-674-4

Keywords

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